From 665d863fce178a8b31721de9f7d9beae4aa76710 Mon Sep 17 00:00:00 2001
From: Hugo Geoffroy <pistache@lebib.org>
Date: Tue, 19 Nov 2019 05:08:49 +0100
Subject: [PATCH] nixos/lxd: add package options for LXC, LXD and ZFS

Currently, LXD always use pkgs.zfs, even if boot.zfs.enableUnstable is set. This
change provides the option to change the LXC, LXD and ZFS packages, and
determines the default ZFS package based on zfs.enableUnstable.
---
 nixos/modules/virtualisation/lxd.nix | 42 +++++++++++++++++++++++-----
 1 file changed, 35 insertions(+), 7 deletions(-)

diff --git a/nixos/modules/virtualisation/lxd.nix b/nixos/modules/virtualisation/lxd.nix
index b4934a86cf5..0e22fb544ad 100644
--- a/nixos/modules/virtualisation/lxd.nix
+++ b/nixos/modules/virtualisation/lxd.nix
@@ -7,6 +7,7 @@ with lib;
 let
 
   cfg = config.virtualisation.lxd;
+  zfsCfg = config.boot.zfs;
 
 in
 
@@ -26,11 +27,38 @@ in
           <command>lxc</command> command line tool, among others.
         '';
       };
+
+      package = mkOption {
+        type = types.package;
+        default = pkgs.lxd;
+        description = ''
+          The LXD package to use.
+        '';
+      };
+
+      lxcPackage = mkOption {
+        type = types.package;
+        default = pkgs.lxc;
+        description = ''
+          The LXC package to use with LXD (required for AppArmor profiles).
+        '';
+      };
+
+      zfsPackage = mkOption {
+        type = types.package;
+        default = with pkgs; if zfsCfg.enableUnstable then zfsUnstable else zfs;
+        defaultText = "pkgs.zfs";
+        description = ''
+          The ZFS package to use with LXD.
+        '';
+      };
+
       zfsSupport = mkOption {
         type = types.bool;
         default = false;
         description = ''
-          enables lxd to use zfs as a storage for containers.
+          Enables lxd to use zfs as a storage for containers.
+
           This option is enabled by default if a zfs pool is configured
           with nixos.
         '';
@@ -54,15 +82,15 @@ in
 
   config = mkIf cfg.enable {
 
-    environment.systemPackages = [ pkgs.lxd ];
+    environment.systemPackages = [ cfg.package ];
 
     security.apparmor = {
       enable = true;
       profiles = [
-        "${pkgs.lxc}/etc/apparmor.d/usr.bin.lxc-start"
-        "${pkgs.lxc}/etc/apparmor.d/lxc-containers"
+        "${cfg.lxcPackage}/etc/apparmor.d/usr.bin.lxc-start"
+        "${cfg.lxcPackage}/etc/apparmor.d/lxc-containers"
       ];
-      packages = [ pkgs.lxc ];
+      packages = [ cfg.lxcPackage ];
     };
 
     systemd.services.lxd = {
@@ -71,14 +99,14 @@ in
       wantedBy = [ "multi-user.target" ];
       after = [ "systemd-udev-settle.service" ];
 
-      path = lib.optional cfg.zfsSupport pkgs.zfs;
+      path = lib.optional cfg.zfsSupport cfg.zfsPackage;
 
       preStart = ''
         mkdir -m 0755 -p /var/lib/lxc/rootfs
       '';
 
       serviceConfig = {
-        ExecStart = "@${pkgs.lxd.bin}/bin/lxd lxd --group lxd";
+        ExecStart = "@${cfg.package.bin}/bin/lxd lxd --group lxd";
         Type = "simple";
         KillMode = "process"; # when stopping, leave the containers alone
         LimitMEMLOCK = "infinity";